Film Formation Apparatus and Method for Forming a Film

ABSTRACT

An apparatus for forming a film having high uniformity in its film thickness distribution is provided. An evaporation source is used in which an evaporation cell, or a plurality of evaporation cells, having a longitudinal direction is formed, and by moving the evaporation source in a direction perpendicular to the longitudinal direction of the evaporation source, a thin film is deposited on a substrate. By making the evaporation source longer, the uniformity of the film thickness distribution in the longitudinal direction is increased. The evaporation source is moved, film formation is performed over the entire substrate, and therefore the uniformity of the film thickness distribution over the entire substrate can be increased.

The present application is a continuation of co-pending U.S. applicationSer. No. 12/467,497, filed May 18, 2009 which is a divisional of U.S.application Ser. No. 09/747,731, filed Dec. 22, 2000 (now U.S. Pat. No.8,119,189 issued Feb. 21, 2012), which are all incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus or a method for forming afilm used in manufacturing an EL (electroluminescence) element having astructure composed of an anode, a cathode, and sandwiching between theanode and the cathode a light emitting material, in particular aself-luminescing organic material (hereafter referred to as an organicEL material), from which EL (Electro Luminescence) is obtained.

2. Description of the Related Art

There are two types of EL display devices, a passive (a simple matrix),and an active (an active matrix), and development of both is beingenthusiastically performed. In particular, active matrix EL displaydevices are in the spotlight at present. Furthermore, organic materialsand inorganic materials exist for an EL material which becomes a lightemitting layer of an EL element, and in addition organic materials aredivided into low molecular weight (monomer) organic EL materials andhigh molecular weight (polymer) organic EL materials. Both are beingvigorously researched, but a film of a low molecular weight organic ELmaterial is mainly formed by evaporation, while a film of a high polymerorganic EL material is mainly formed by application.

In order to manufacture a color display EL display device, it isnecessary to form films of EL materials which emit different colors, foreach pixel. However, in general EL materials are weak with respect towater and oxygen, and patterning by photolithography cannot beperformed. It is therefore necessary to form the films at the same timeas patterning.

The most general method is a method for forming a mask, made from ametallic plate or a glass plate and having an open portion formed in it,between the substrate onto which a film is formed and an evaporationsource. In this case, the vaporized EL material from the evaporationsource passes through only the open portion to thereby form the filmselectively, and therefore it is possible to form an EL layer in whichfilm formation and patterning are performed simultaneously.

With a conventional evaporation apparatus, the EL material which fliesoff in a radial shape from one evaporation source accumulates on asubstrate, forming a thin film, and therefore, considering the distancethat the EL material covers, a way of substrate positioning was devised.For example, a method of fixing a substrate to a circular cone shapedsubstrate holder, making the distances from the evaporation source tothe substrate all equal, is performed.

However, when employing a multi-beveling process in which a plurality ofpanels are manufactured on a large size substrate, the substrate holderbecomes extremely large if the above stated process is performed, andthis leads to the main body of the film formation apparatus becominglarge. Further, the substrate is planar when performing by single waferprocessing as well, and therefore the distances from the evaporationsource differs within the surface of the substrate, and a problemremains in that it is difficult to deposit at a uniform film thickness.

In addition, if the distance between the evaporation source and theshadow mask is not made longer when using a large size substrate, thevaporized EL material does not sufficiently spread, and it becomesdifficult to form a uniform thin film over the entire substrate surface.Maintaining this distance also encourages making the apparatus largesize.

SUMMARY OF THE INVENTION

The present invention is made in view of the above stated problems, andan object of the present invention is to provide a film formationapparatus capable of forming a thin film having a highly uniform filmthickness distribution at high throughput. Further, an object of thepresent invention is to provide a method of forming a film using thefilm formation apparatus of the present invention.

An evaporation source in which an evaporation cell having a longitudinaldirection (a portion in which a thin film material for evaporation isplaced), or a plurality of the evaporation cells, are formed is used inthe present invention. By moving the evaporation source in a directionperpendicular to the longitudinal direction of the evaporation source, athin film is formed. Note that, “having a longitudinal direction”indicates a long and thin rectangular shape, a long and thin ellipticalshape, or a linear shape. It is preferable that the length in thelongitudinal direction be longer than the length of one side of asubstrate for the present invention because processing can be performedin one sweep. Specifically, the length may be from 300 mm to 1200 mm(typically between 600 and 800 mm).

The positional relationship between the evaporation source of thepresent invention and the substrate is shown in FIGS. 1A to 1C. FIG. 1Ais a top view, FIG. 1B is a cross sectional diagram of FIG. 1A cut alongthe line segment B-B′, and FIG. 10 is a cross sectional diagram of FIG.1A cut along the line segment C-C′. Note that, common symbols are usedin FIGS. 1A to 10.

As shown in FIG. 1A, a shadow mask 102 is placed below a substrate 101,and in addition, a rectangular shaped evaporation source 104, in which aplurality of evaporation cells 103 are lined up on a straight line, isplaced below the shadow mask 102. Note that, throughout thisspecification, the term substrate includes a substrate and thin filmsformed on that substrate. Further, the term substrate surface indicatesthe substrate surface on which the thin films are formed.

The length of the longitudinal direction of the evaporation source 104is longer than the length of one side of the substrate 101, and amechanism for moving the evaporation source 104 in a direction shown byan arrow (a direction perpendicular to the longitudinal direction of theevaporation source 104) is prepared. By then moving the evaporationsource 104, a thin film can be formed over the entire surface of thesubstrate. Note that, when the length of the longitudinal direction isshorter than that of one side of the substrate, the thin film may beformed by repeating a plurality of scans. Furthermore, a lamination ofthe same thin film may be formed by repeatedly moving the evaporationsource 104.

The thin film material vaporized by each of the evaporation cells 103 isscattered in the upward direction, passes through open portions (notshown in the figures) formed in the shadow mask 102, and accumulates onthe substrate 101. The thin film is thus selectively deposited on thesubstrate 101. A region in which the thin film material scattered fromone evaporation cell 103 forms a film overlaps with a region in whichthe thin film material scattered from an adjoining evaporation cell 103forms a film. By mutually overlapping the regions in which the film isdeposited, the film is formed in a rectangular shape region.

The uniformity in film thickness of a thin film can thus be greatlyimproved with the present invention by using the evaporation sourcehaving a plurality of evaporation cells lined up, and by irradiatingfrom a line instead of conventional irradiation from a point. Inaddition, by moving the rectangular shape evaporation source below thesubstrate surface, film formation can be performed at high throughput.

Additionally, it is not necessary to make the distance between theevaporation source 104 and the shadow mask 102 longer with the presentinvention, and evaporation can be performed in a state of extremecloseness. This is because a plurality of evaporation cells are formedin alignment, and even if the scattering distance of the thin filmmaterial is short, film formation can be performed simultaneously fromthe central portion to the edge portion of the substrate. This effect isgreater the higher the density at which the evaporation cells 103 arelined up.

The distance from the evaporation source 104 to the shadow mask 102 isnot particularly limited because it differs depending upon the densityat which the evaporation cells 103 are formed. However, if it is tooclose, then it becomes difficult to form a uniform film from the centerportion to the edge portion, and if it is too far, there will be nochange from conventional evaporation by irradiating from a point.Therefore, if the gap between evaporation cells 103 is taken as “a”, itis preferable to make the distance between the evaporation source 104and the shadow mask 102 from 2 a to 100 a (more preferably from 5 a to50 a).

With the film formation apparatus of the present invention structured asabove, uniformity of the distribution of film thickness of a thin filmin a rectangular shape, elliptical shape, or a linear shape region ismaintained by using the evaporation source, and by moving theevaporation source on top of that region, it becomes possible to form athin film having high uniformity over the entire surface of thesubstrate. Further, this is not evaporation from a point, and thereforethe distance between the evaporation source and the substrate can bemade shorter, and the uniformity of film thickness can be furtherincreased.

Furthermore, it is effective to add means for generating a plasma withina chamber in the film formation apparatus of the present invention. Byperforming a plasma process in accordance with oxygen gas or a plasmaprocess in accordance with a gas containing fluorine, thin filmsdeposited on the chamber walls are removed, and cleaning of the insideof the chamber can be performed. Parallel-plate electrodes may be formedwithin the chamber, and a plasma may be generated between the plates asthe means for generating the plasma.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1C are diagrams showing a structure of an evaporationsource;

FIGS. 2A and 2B are diagrams showing a structure of an evaporationchamber;

FIG. 3 is a diagram showing a structure of an evaporation chamber;

FIG. 4 is a diagram showing a structure of a film formation apparatus;

FIG. 5 is a diagram showing a structure of a film formation apparatus;

FIG. 6 is a diagram showing a structure of a film formation apparatus;

FIG. 7 is a diagram showing a structure of a film formation apparatus;and

FIG. 8 is a diagram showing a structure of a film formation apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment Mode

A structure of an evaporation chamber prepared in a film formationapparatus of the present invention is shown in FIGS. 2A and 2B. FIG. 2Ais a top view of the evaporation chamber, and FIG. 2B is a crosssectional diagram. Note that common symbols are used for commonportions. Further, an example of forming an EL (electroluminescence)film as a thin film is shown in the embodiment mode.

In FIG. 2A, reference numeral 201 denotes a chamber, and referencenumeral 202 denotes a substrate conveyor opening, from which substrateis conveyed to the inside portion of the chamber 201. A conveyedsubstrate 203 is set in a substrate holder 204, and is conveyed in to afilm formation portion 206 by a conveyor rail 205 a, as shown by anarrow 205 b.

When the substrate 203 is conveyed to a film formation portion 206, ashadow mask 208 fixed to a mask holder 207 approaches the substrate 203.Note that, a metallic plate is used as the material of the shadow mask208 in this embodiment mode. (See FIG. 2B) Further, open portions 209are formed having a rectangular shape, elliptical shape, or linear shapein the shadow mask 208 in this embodiment mode. The shape of the openingportions is not limited, of course, and a matrix shape or a net shapemay also be formed.

At this point in the embodiment mode, this is a structure in which anelectromagnet 210 approaches the substrate 203, as shown in FIG. 2B.When a magnetic field is formed by the electromagnet 210, the shadowmask 208 is drawn to the substrate 203, and is maintained at apredetermined gap. This gap is secured by a plurality of projections 301formed in the shadow mask 208, as shown in FIG. 3.

This type of structure is particularly effective when the substrate 203is a large size substrate exceeding 300 mm. If the substrate 203 islarge size, then deflection (warp) is generated by the weight of thesubstrate itself. However, the substrate 203 can also be pulled towardthe electromagnet 210 and the flexure can be canceled provided that theshadow mask 208 is drawn toward the substrate 203 side by theelectromagnet 210. Note that, as shown in FIG. 4, it is preferable toform projections 401 in the electromagnet 210, and to maintain a gapbetween the substrate 203 and the electromagnet 210.

When the gap between the substrate 203 and the shadow mask 208 issecured, an evaporation source 212, on which evaporation cells 211having a longitudinal direction are formed, is then moved in thedirection of the arrow 213. An EL material formed in the inside portionof the evaporation cells is vaporized by being heated while being moved,and is scattered within the chamber of the film formation portion 206.Note that the distance between the evaporation source 212 and thesubstrate 203 can be made extremely short for the case of the presentinvention, and therefore adhesion of the EL material to a drive portion(a portion for driving the evaporation source, the substrate holder, orthe mask holder) within the chamber can be minimized.

The evaporation source 212 is scanned from one end of the substrate 203to the other end. As shown in FIG. 2A, the length of the longitudinaldirection of the evaporation source 212 is sufficiently long in theembodiment mode, and therefore it can be moved over the entire surfaceof the substrate 203 by scanning once.

After a film is formed from a red, green, or blue color EL material (redhere) as above, the magnetic field of the electromagnet 210 is switchedoff, the mask holder 207 is dropped down, and the distance between theshadow mask 208 and the substrate 203 increases. The substrate holder204 is then shifted over by one pixel portion, the mask holder 207 israised again, and the shadow mask 208 and the substrate 203 are made tocome closer. In addition, a magnetic field is formed by theelectromagnet 210, and deflection (warp) of the shadow mask 208 and thesubstrate 203 is eliminated. The evaporation cell is changed next, andfilm formation of a red, green, or blue EL material (green here) isperformed.

Note that, a structure in which the substrate holder 204 is shifted byone pixel portion is shown here, but the mask holder 204 may also beshifted by one pixel portion.

After all film formation of red, green, and blue EL materials by thistype of repetition, the substrate 203 is lastly conveyed to thesubstrate conveyor opening 202, and is removed from the chamber 201 by arobot arm (not shown in the figures). Film formation of the EL filmsusing the present invention is thus completed.

Embodiment 1

An explanation of a film formation apparatus of the present invention isexplained using FIG. 5. In FIG. 5, reference numeral 501 denotes aconveyor chamber. A conveyor mechanism 502 is prepared in the conveyorchamber 501, and conveyance of a substrate 503 is performed. Theconveyor chamber 501 has a reduced pressure atmosphere, and is connectedto each processing chamber by a gate. Delivery of the substrate to eachprocessing chamber is performed by the conveyor mechanism 502 when thegates are open. Further, it is possible to use an evacuation pump suchas an oil-sealed rotary pump, a mechanical booster pump, aturbo-molecular pump, and a cryo-pump in lowering the pressure of theconveyor chamber 501, but a cryo-pump, which is effective in removingmoisture, is preferable.

An explanation regarding each processing chamber is made below. Notethat the conveyor chamber 501 has a reduced pressure atmosphere, andtherefore an evacuation pump (not shown in the figure) is prepared ineach processing chamber directly connected to the conveyor chamber 501.The above stated oil-sealed rotary pump, mechanical booster pump,turbo-molecular pump, and cryo-pump are used as the evacuation pump.

First, reference numeral 504 denotes a load chamber for performingsubstrate setting, and it is also an unload chamber. The load chamber504 is connected to the conveyor chamber 501 by a gate 500 a, and acarrier (not shown in the figure) on which the substrate 503 is set isarranged here. Note that the load chamber 504 may also be separated intoa substrate loading chamber and a substrate unloading chamber. Further,the above evacuation pump and a purge line for introducing high puritynitrogen gas or noble gas are prepared for the load chamber 504.

Note that a substrate on which process through the formation of atransparent conducting film, which becomes an anode of an EL element hasbeen conducted, is used as the substrate 503 in Embodiment 1. Thesubstrate 503 is set in the carrier with the surface on which the filmsare formed facing downward. This is in order to make a face-down method(also referred to as a deposition-up method) easier to perform whenlater performing film formation by evaporation. The face down methoddenotes a method in which film formation is performed with the substratesurface onto which a film is to be formed facing downward, and adhesionof refuse (dirt) or the like can be suppressed by this method.

Next, reference numeral 505 denotes a processing chamber for processinga surface of an anode or a cathode of an EL element (in Embodiment 1, ananode), and the processing chamber 505 is connected to the conveyorchamber 501 by a gate 500 b. The processing chamber can be changedvariously depending upon the manufacturing process of the EL element,and in Embodiment 1 heat treatment of the surface of the anode made fromthe transparent conducting film can be performed at between 100 and 120°C. in oxygen while irradiating ultraviolet light. This type ofpre-process is effective when processing the anode surface of the ELelement.

Next, reference numeral 506 denotes an evaporation chamber for filmdeposition of an organic EL material by evaporation, and is referred toas an evaporation chamber (A). The evaporation chamber (A) 506 isconnected to the conveyor chamber 501 through a gate 500 c. InEmbodiment 1 an evaporation chamber having the structure shown in FIGS.2A and 2B is used as the evaporation chamber (A) 506.

In a film formation portion 507 of the evaporation chamber (A) 506,first a hole injecting layer is deposited over the entire substratesurface, then a light emitting layer for emitting red color light isformed, next a light emitting layer for emitting green color light isformed, and lastly a light emitting layer for emitting blue color lightis formed. Note that any known materials may be used as the holeinjecting layer, the red color light emitting layer, the green colorlight emitting layer, and the blue color light emitting layer.

The evaporation chamber (A) 506 has a structure which is capable ofswitching in correspondence with the type of organic material of thefilm formation evaporation source. Namely, a preparation chamber 508 forstoring a plurality of types of evaporation sources is connected to theevaporation chamber (A) 506, and evaporation source switching isperformed by an internal conveyor mechanism. The evaporation sourcetherefore changes when the organic EL material for film formationchanges. Further, the same mask of shadow mask is moved by one pixelportion whenever the organic EL material for film formation is switched.

Note that FIGS. 2A and 2B may be referred to regarding film formationprocesses occurring within the evaporation chamber (A) 506.

Next, reference numeral 509 denotes an evaporation chamber for filmformation of a conducting film (a metallic film which becomes a cathodeis used in Embodiment 1), which becomes an anode or a cathode of the ELelement, by evaporation, and is referred to as an evaporation chamber(B). The evaporation chamber (B) 509 is connected to the conveyorchamber 501 through a gate 500 d. An evaporation chamber having thestructure shown in FIGS. 2A and 2B is used as the evaporation chamber(B) 509 in Embodiment 1. In a film formation portion 510 within theevaporation chamber (B) 509, an Al—Li alloy film (an alloy film ofaluminum and lithium) is deposited as the conducting film which becomesthe EL element cathode.

Note that it is also possible to co-evaporate an element residing ingroup 1 or group 2 of the periodic table, and aluminum. Co-evaporationrefers to evaporation in which cells are heated at the same time, anddifferent materials are combined at the stage of film formation.

Next, reference numeral 511 denotes a sealing chamber (also referred toas an enclosing chamber or a globe box), and is connected to the loadchamber 504 through a gate 500 e. A process for final hermetic sealingof the EL element is performed in the sealing chamber 511. This processis one in which the formed EL element is protected from oxygen andmoisture, and a means for mechanically sealing by a sealing material, ora means for sealing by a thermally hardened resin or an ultravioletlight hardened resin is used.

Glass, ceramic, plastic, and metal can be used as the sealing material,but when light is irradiated onto the sealing material side, thematerial must have transparency. Further, when the sealing material andsubstrate on which the above EL element is formed are joined using athermal hardened resin or an ultraviolet light hardened resin, the resinis hardened by heat treatment or by ultraviolet light irradiationprocessing, forming an airtight space. It is also effective to form adrying agent, typically barium oxide, within the airtight space.

Further, it is also possible to fill the space between the sealingmaterial and the substrate on which the EL element is formed by athermal hardened resin or an ultraviolet light hardened resin. In thiscase, it is effective to add a drying agent, typically barium oxide,within the thermal hardened resin or the ultraviolet light hardenedresin.

A mechanism for irradiating ultraviolet light (hereafter referred to asan ultraviolet light irradiation mechanism) 512 is formed on an internalportion of the sealing chamber 511, and the film formation apparatusshown in FIG. 5 has a structure in which an ultraviolet light hardenedresin is hardened by ultraviolet light emitted from the ultravioletlight irradiation mechanism 512. Further, it is possible to reduce thepressure of the inside portion of the sealing chamber 511 by attachingan evacuation pump. When mechanically performing the above sealingprocesses by using robot operation, oxygen and moisture can be preventedfrom mixing in by performing the processes under reduced pressure.Furthermore, it is also possible to pressurize the inside portion of thesealing chamber 511. In this case pressurization is performed by a highpurity nitrogen gas or noble gas while purging, and an incursion of acontaminant such as oxygen from the atmosphere is prevented.

Next, a delivery chamber (a pass box) 513 is connected to the sealingchamber 511. A conveyor mechanism (B) 514 is formed in the deliverychamber 513, and the substrate on which the EL element has beencompletely sealed in the sealing chamber 511 is conveyed to the deliverychamber 513. It is possible to also make the delivery chamber 513reduced pressure by attaching an evacuation pump. The delivery chamber513 is equipment used so that the sealing chamber 511 is not directlyexposed to the atmosphere, and the substrate is removed from here.

It thus becomes possible to manufacture an EL display device having highreliability by using the film formation apparatus shown in FIG. 5because processing can be finished up through the point, withoutexposure to the atmosphere, at which the EL element is completely sealedinto an airtight space.

Embodiment 2

A case of using a film formation apparatus of the present invention in amulti-chamber method (also referred to as a cluster tool method) isexplained using FIG. 6. Reference numeral 601 denotes a conveyor chamberin FIG. 6. A conveyor mechanism (A) 602 is prepared in the conveyorchamber 601, and conveyance of a substrate 603 is performed. Theconveyor chamber 601 has a reduced pressure atmosphere, and is connectedto each processing chamber by a gate. Delivery of the substrate to eachprocessing chamber is performed by the conveyor mechanism (A) 602 whenthe gates are open. Further, it is possible to use an evacuation pumpsuch as an oil-sealed rotary pump, a mechanical booster pump, aturbo-molecular pump, and a cryo-pump in lowering the pressure of theconveyor chamber 601, but a cryo-pump, which is effective in removingmoisture, is preferable.

An explanation regarding each processing chamber is made below. Notethat the conveyor chamber 601 has a reduced pressure atmosphere, andtherefore an evacuation pump (not shown in the figure) is prepared ineach processing chamber directly connected to the conveyor chamber 601.The above stated oil-sealed rotary pump, mechanical booster pump,turbo-molecular pump, and cryo-pump is used as the evacuation pump.

First, reference numeral 604 denotes a load chamber for performingsubstrate setting, and it is also called an unload chamber. The loadchamber 604 is connected to the conveyor chamber 601 by a gate 600 a,and a carrier (not shown in the figure) on which the substrate 603 isset is arranged here. Note that the load chamber 604 may also beseparated into a substrate loading chamber and a substrate unloadingchamber. Further, the above evacuation pump and a purge line forintroducing high purity nitrogen gas or noble gas are prepared for theload chamber 604.

Next, reference numeral 605 denotes a preprocessing chamber forprocessing a surface of an anode or a cathode of an EL element (inEmbodiment 2, an anode), and the processing chamber 605 is connected tothe conveyor chamber 601 by a gate 600 b. The preprocessing chamber canbe changed variously depending upon the manufacturing process of the ELelement, and in Embodiment 2 heat treatment of the surface of the anodemade from the transparent conducting film can be performed at between100 and 120° C. in oxygen while irradiating ultraviolet light. This typeof pre-process is effective when processing the anode surface of the ELelement.

Next, reference numeral 606 denotes an evaporation chamber for filmdeposition of an organic EL material by evaporation, and is referred toas an evaporation chamber (A). The evaporation chamber (A) 606 isconnected to the conveyor chamber 601 through a gate 600 c. InEmbodiment 2 an evaporation chamber having the structure shown in FIGS.2A and 2B is used as the evaporation chamber (A) 606.

In a film formation portion 607 of the evaporation chamber (A) 606, ahole injecting layer is first deposited over the entire substratesurface, then a light emitting layer for emitting red color light isformed. Accordingly, an evaporation source and a shadow mask areprovided with two types of each corresponding to the organic material tobe the hole injecting layer and the red light emitting layer, and arestructured to be capable of switching. Note that known materials may beused as the hole injecting layer, and the red color light emittinglayer.

Next, reference numeral 608 denotes an evaporation chamber for filmformation of an organic EL material by evaporation, and is referred toas an evaporation chamber (B). The evaporation chamber (B) 608 isconnected to the conveyor chamber 601 through a gate 600 d. InEmbodiment 2, an evaporation chamber with the structure shown in FIGS.2A and 2B is used as the evaporation chamber (B) 608. A light emittinglayer for emitting green color light is deposited in a film formationportion 609 within the evaporation chamber (B) 608 in Embodiment 2. Notethat a known material may be used as the light emitting layer foremitting green color light in Embodiment 2.

Next, reference numeral 610 denotes an evaporation chamber for filmformation of an organic EL material by evaporation, and is referred toas an evaporation chamber (C). The evaporation chamber (C) 610 isconnected to the conveyor chamber 601 through a gate 600 e. InEmbodiment 2, an evaporation chamber with the structure shown in FIGS.2A and 2B is used as the evaporation chamber (C) 610. Alight emittinglayer for emitting blue color light is deposited in a film formationportion 611 within the evaporation chamber (C) 610 in Embodiment 2. Notethat a known material may be used as the light emitting layer foremitting blue color light in Embodiment 2.

Next, reference numeral 612 denotes an evaporation chamber for filmformation of a conducting film, which becomes an anode or a cathode ofthe EL element, by evaporation (a metallic film which becomes a cathodeis used in Embodiment 2), and is referred to as an evaporation chamber(D). The evaporation chamber (D) 612 is connected to the conveyorchamber 601 through a gate 600 f. An evaporation chamber having thestructure shown in FIGS. 2A and 2B is used as the evaporation chamber(D) 612 in Embodiment 2. In a film formation portion 613 within theevaporation chamber (D) 612, an Al—Li alloy film (an alloy film ofaluminum and lithium) is deposited as the conducting film which becomesthe EL element cathode. Note that it is also possible to co-evaporate anelement residing in group 1 or group 2 of the periodic table, andaluminum.

Next, reference numeral 614 denotes a sealing chamber, and is connectedto the load chamber 604 through a gate 600 g. For explanation of thesealing chamber 614 refer to Embodiment 1. Further, an ultraviolet lightirradiation mechanism 615 is formed in the inside portion of the sealingchamber 614, similar to Embodiment 1. In addition, a delivery chamber616 is connected to the sealing chamber 615. A conveyor mechanism (B)617 is formed in the delivery chamber 616, and the substrate, on whichthe EL element has been completely sealed in the sealing chamber 614, isconveyed to the delivery chamber 616. Embodiment 1 may be referred tofor an explanation of the delivery chamber 616.

It thus becomes possible to manufacture an EL display device having highreliability by using the film formation apparatus shown in FIG. 6because processing can be finished up through the point, withoutexposure to the atmosphere, at which the EL element is completely sealedinto an airtight space.

Embodiment 3

A case of using a film formation apparatus of the present invention inan in-line method is explained using FIG. 7. Reference numeral 701denotes a load chamber in FIG. 7, and conveyance of a substrate isperformed here. An evacuation system 700 a is prepared in the loadchamber 701, and the evacuation system 700 a has a structure containinga first valve 71, a turbo-molecular pump 72, a second valve 73, and arotary pump (oil-sealed rotary pump) 74.

The first valve 71 is a main valve, and there are cases when it alsocombines a conductance valve, and there are also cases when a butterflyvalve is used. The second valve 73 is a fore valve, and the second valve73 is opened first, and the load chamber 701 is roughly reduced inpressure by the rotary pump 74. The first valve 71 is opened next, andthe pressure is reduced by the turbo-molecular pump 72 until a highvacuum is reached. Note that it is possible to use a mechanical boosterpump or a cryo-pump as a substitute for the turbo-molecular pump, butthe cryo-pump is particularly effective in removing moisture.

Next, reference numeral 702 denotes a preprocessing chamber forprocessing a surface of an anode or a cathode of an EL element (inEmbodiment 3, an anode), and the preprocessing chamber 702 is preparedwith an evacuation system 700 b. Further, it is hermetically sealed offfrom the load chamber 701 by a gate not shown in the figure. Thepreprocessing chamber 702 can be changed variously depending upon themanufacturing process of the EL element, and in Embodiment 3 heattreatment of the surface of the anode made from the transparentconducting film can be performed at between 100 and 120° C. in oxygenwhile irradiating ultraviolet light.

Next, reference numeral 703 denotes an evaporation chamber for filmdeposition of an organic. EL material by evaporation, and is referred toas an evaporation chamber (A). Further, it is hermetically sealed offfrom the load chamber 702 by a gate not shown in the figure. Theevaporation chamber (A) 703 is prepared with an evacuation system 700 c.In Embodiment 3 an evaporation chamber having the structure shown inFIGS. 2A and 2B is used as the evaporation chamber (A) 703.

A substrate 704 conveyed to the evaporation chamber (A) 703, and anevaporation source 705 prepared in the evaporation chamber (A) 703, aremoved in the direction of the arrows, respectively, and film formationis performed. Note that FIGS. 2A and 2B may be referred to regardingdetailed operation of the evaporation chamber (A) 703. A hole injectinglayer is deposited in the evaporation chamber (A) 703 in Embodiment 3. Aknown material may be used as the hole injecting layer.

Next, reference numeral 706 denotes an evaporation chamber for filmformation of an organic EL material by evaporation, and is referred toas an evaporation chamber (B). The evaporation chamber (B) 706 isprepared with an evacuation system 700 d. Further, it is hermeticallysealed off from the evacuation chamber (A) 703 by a gate not shown inthe figure. An evaporation chamber having the structure shown in FIGS.2A and 2B is formed as the evaporation chamber (B) 706 in Embodiment 3.The explanation of FIGS. 2A and 2B may therefore be referred toregarding detailed operation of the evaporation chamber (B) 706.Further, a light emitting layer for emitting red color light isdeposited in the evaporation chamber (B) 706. A known material may beused as the light emitting layer which emits red color light.

Next, reference numeral 707 denotes an evaporation chamber for filmformation of an organic EL material by evaporation, and is referred toas an evaporation chamber (C). The evaporation chamber (C) 707 isprepared with an evacuation system 700 e. Further, it is hermeticallysealed off from the evacuation chamber (B) 706 by a gate not shown inthe figure. An evaporation chamber having the structure shown in FIGS.2A and 2B is formed as the evaporation chamber (C) 707 in Embodiment 3.The explanation of FIGS. 2A and 2B may therefore be referred toregarding detailed operation of the evaporation chamber (C) 707.Further, a light emitting layer for emitting green color light isdeposited in the evaporation chamber (C) 707. A known material may beused as the light emitting layer which emits green color light.

Next, reference numeral 708 denotes an evaporation chamber for filmformation of an organic EL element by evaporation, and is referred to asan evaporation chamber (D). The evaporation chamber (D) 708 is preparedwith an evacuation system 700 f. Further, it is hermetically sealed offfrom the evacuation chamber (C) 707 by a gate not shown in the figure.An evaporation chamber having the structure shown in FIGS. 2A and 2B isformed as the evaporation chamber (D) 708 in Embodiment 3. Theexplanation of FIGS. 2A and 2B may therefore be referred to regardingdetailed operation of the evaporation chamber (D) 708. Further, a lightemitting layer for emitting blue color light is deposited in theevaporation chamber (D) 708. A known material may be used as the lightemitting layer which emits blue color light.

Next, reference numeral 709 denotes an evaporation chamber for filmformation of a conducting film (a metallic film which becomes a cathodeis used in Embodiment 3), which becomes an anode or a cathode of the ELelement, by evaporation, and is referred to as an evaporation chamber(E). The evaporation chamber (E) 709 is prepared with an evacuationsystem 700 g. Further, it is hermetically sealed off from the evacuationchamber (D) 708 by a gate not shown in the figure. An evaporationchamber having the structure shown in FIGS. 2A and 2B is formed as theevaporation chamber (E) 709 in Embodiment 3. The explanation of FIGS. 2Aand 2B may therefore be referred to regarding detailed operation of theevaporation chamber (E) 709.

An Al—Li alloy film (an alloy film of aluminum and lithium) is depositedin the evaporation chamber (E) 709 as the conducting film which becomesthe EL element cathode. Note that it is also possible to co-evaporate anelement residing in group 1 or group 2 of the periodic table, andaluminum.

Next, reference numeral 710 denotes a sealing chamber, and it isprepared with an evacuation system 700 h. Further, it is hermeticallysealed off from the evacuation chamber (E) 709 by a gate not shown inthe figure. Embodiment 1 may be referred to regarding an explanation ofthe sealing chamber 710. Furthermore, an ultraviolet light irradiationmechanism is provided on the inside portion of the sealing chamber 710,similar to Embodiment 1.

Finally, reference numeral 711 denotes an unload chamber, and it isprepared with an evacuation system 700 i. The substrate on which the ELelement is formed is removed from here.

It thus becomes possible to manufacture an EL display device having highreliability by using the film formation apparatus shown in FIG. 7because processing can be finished up through the point, withoutexposure to the atmosphere, at which the EL element is completely sealedinto an airtight space. An EL display device can furthermore bemanufactured at a high throughput in accordance with the in-line method.

Embodiment 4

A case of using a film formation apparatus of the present invention inan in-line method is explained using FIG. 8. Reference numeral 801denotes a load chamber in FIG. 8, and conveyance of a substrate isperformed here. An evacuation system 800 a is prepared in the loadchamber 801, and the evacuation system 800 a has a structure containinga first valve 81, a turbo-molecular pump 82, a second valve 83, and arotary pump (oil-sealed rotary pump) 84.

Next, reference numeral 802 denotes a preprocessing chamber forprocessing a surface of an anode or a cathode of an EL element (inEmbodiment 4, an anode), and the preprocessing chamber 802 is preparedwith an evacuation system 800 b. Further, it is hermetically sealed offfrom the load chamber 801 by a gate not shown in the figure. Thepreprocessing chamber 802 can be changed variously depending upon themanufacturing process of the EL element, and in Embodiment 4 heattreatment of the surface of the anode made from the transparentconducting film can be performed at between 100 and 120° C. in oxygenwhile irradiating ultraviolet light.

Next, reference numeral 803 denotes an evaporation chamber for filmdeposition of an organic EL material by evaporation, and the evaporationchamber 803 is prepared with an evacuation system 800 c. In Embodiment 4an evaporation chamber having the structure shown in FIGS. 2A and 2B isused as the evaporation chamber 803. A substrate 804 conveyed to theevaporation chamber 803, and an evaporation source 805 prepared in theevaporation chamber 803, are moved in the direction of the arrows,respectively, and film formation is performed.

In Embodiment 4, it is preferable to switch the evaporation source 803or the shadowmask (not shown) at the time of film deposition in theevaporation chamber 803 in order to form a conductive film to be holeinjection layer, a red light emitting layer, a green light emittinglayer, a blue light emitting layer or a cathode. In Embodiment 4, theevaporation chamber 803 is connected with a reserve chamber 806, inwhich the evaporation source and the shadow mask are stored to switchappropriately.

Next, reference numeral 807 denotes a sealing chamber, and it isprepared with an evacuation system 800 d. Further, it is hermeticallysealed off from the evacuation chamber 803 by a gate not shown in thefigure. Embodiment 1 may be referred to regarding an explanation of thesealing chamber 807. Furthermore, an ultraviolet light irradiationmechanism (not shown in the figure) is provided on the inside portion ofthe sealing chamber 807, similar to Embodiment 1.

Finally, reference numeral 808 denotes an unload chamber, and it isprepared with an evacuation system 800 e. The substrate on which the ELelement is formed is removed from here.

It thus becomes possible to manufacture an EL display device having highreliability by using the film formation apparatus shown in FIG. 8because processing can be finished up through to the point, at which theEL element is completely sealed into an airtight space without exposureto the atmosphere. An EL display device can furthermore be manufacturedat a high throughput in accordance with the in-line method.

By using the film formation apparatus of the present invention, itbecomes possible to perform film formation, at high throughput, of athin film having high uniformity in its film thickness distribution onthe substrate surface.

What is claimed is:
 1. (canceled)
 2. A method of manufacturing a lightemitting device comprising a step of: depositing an organic materialover a substrate by evaporating the organic material from an evaporationsource, wherein the evaporation source comprises a plurality of discreteevaporation cells separated from each other, wherein each of theplurality of discrete evaporation cells contains the organic material,wherein the evaporation source has a length along a first direction anda width along a second direction orthogonal to the first direction, thelength being greater than the width, wherein the plurality of discreteevaporation cells is arranged along the first direction, wherein, whenthe organic material is evaporated, a relative location of theevaporation source with respect to the substrate is changed along thesecond direction, and wherein the evaporation of the organic material isinitiated by heating the plurality of discrete evaporation cells.
 3. Themethod according to claim 2, wherein the light emitting device is adisplay device.
 4. The method according to claim 2, wherein, when therelative location is changed by moving the substrate.
 5. The methodaccording to claim 2, wherein the length of the evaporation source isfrom 300 mm to 1200 mm.
 6. The method according to claim 2, wherein theevaporation of the organic material from the plurality of evaporationcells is performed at the same time.
 7. A method of manufacturing alight emitting device comprising a step of: depositing an organicmaterial over a substrate through a shadow mask attached to thesubstrate by evaporating the organic material from an evaporationsource, wherein the evaporation source comprises a plurality of discreteevaporation cells separated from each other, wherein each of theplurality of discrete evaporation cells contains the organic material,wherein the evaporation source has a length along a first direction anda width along a second direction orthogonal to the first direction, thelength being greater than the width, wherein the plurality of discreteevaporation cells is arranged along the first direction, wherein, whenthe organic material is evaporated, a relative location of theevaporation source with respect to the substrate is changed along thesecond direction, wherein the evaporation of the organic material isinitiated by heating the plurality of discrete evaporation cells,wherein a distance between the shadow mask and the evaporation source is50 a or less where “a” is a gap between adjacent ones of the pluralityof discrete evaporation cells.
 8. The method according to claim 7,wherein the distance is equal to 2 a or larger.
 9. The method accordingto claim 7, wherein the light emitting device is a display device. 10.The method according to claim 7, wherein, when the relative location ischanged by moving the substrate.
 11. The method according to claim 7,wherein the length of the evaporation source is from 300 mm to 1200 mm.12. The method according to claim 7, wherein the evaporation of theorganic material from the plurality of evaporation cells is performed atthe same time.